What are faulted entities and what the difference between them and 'usual' entities? where can I read about that?
ADC has some documentation on this topic:
Faulting reduces the amount of memory your application consumes. A fault is a placeholder object that represents a managed object that has not yet been fully realized, or a collection object that represents a relationship:
All objects are loaded on demand to reduce memory usage. override -(void) awakeFromFetch/Insert and -(void) willTurnIntoFault to do custom initialization
ADC on Faulting and Uniquing